1. Field of the Invention
The present invention relates to a method and apparatus for dielectric breakdown of a conductive adhesive on a suspension interconnect of a hard disk drive to reduce the severity of electrostatic events encountered by a head slider coupled to the interconnect.
2. Background Information
Hard disk drives contain a plurality of magnetic heads that are coupled to rotating disks. The heads write and read information by magnetizing and sensing the magnetic fields of the disk surfaces. Typically the magnetic heads include a write element for magnetizing the disks and a separate read element for sensing the magnetic field of the disks. The read element is typically constructed using a magneto-resistive material that has a resistance that varies with the magnetic field of the disk. Heads with magneto-resistive read elements are commonly referred to as magneto-resistive (MR) and giant magneto-resistive (GMR) heads.
Each head is mechanically coupled to a head slider. The head slider is attached to a flexure arm to create a subassembly known as a head suspension assembly (HSA). The HSA comprises a subassembly of a known head gimbal assembly (HGA). The HGA's are attached to an actuator arm. The actuator arm has a voice coil motor that can move the heads across the surfaces of the disks.
Information is stored in radial tracks that extend across the surfaces of each disk. Each track is typically divided up into a number of segments or sectors. The voice coil motor and actuator arm can move the heads to different tracks of the disks and to different sectors of each track.
A suspension interconnect extends along the length of the flexure arm and connects the head to a preamplifier device of the voice coil motor. The suspension interconnect typically comprises a pair of conductive write traces and a pair of conductive read traces formed on a stainless steel lamina.
Changes in the geometry of the flexure may cause the read/write heads to contact the surface of the disk. If the read/write heads contact the surface of the disk, electrostatic charging may occur. The electrostatic discharge (ESD) that occurs when the head contacts the disk surface may jump to the head and may severely damage or destroy the head.
An electrostatic discharge may also be formed on the head during the build processes of the HSA, HGA, and hard disk drive. Each ESD event that the head is exposed to may significantly shorten the life of the head and head slider.
Accordingly, there exists a need for an interconnect design that may reduce the head and head slider's exposure to severe ESD events.